SCIENTIFIC OBJECTIVE:Study of variability and dynamics of the outer solar
atmospheric layers in solar network using line intensities and Doppler
shifts of the chromospheric, transition region and coronal emission lines
is proposed.
Network located in the quiet atmosphere, in a coronal hole as well as
network connected with loops outside active regions will be investigated
searching for correlations between the line intensities and the Doppler shifts
of different spectral lines.
In particular effects of network transient events on mutual
relations of the atmospheric layers in/above network will be determined.
Limitations on the possible physical
mechanisms which control energy transfer and mass motion in the
network of the solar outer atmosphere will be derived. Relation
of the emergence and motions of the photospheric magnetic flux to
these mechanisms will be analyzed.

SCIENTIFIC JUSTIFICATION:
Previous observations performed with different instruments (HRTS, SOHO/CDS,
SOHO/SUMER) have revealed that the upper chromosphere, transition region and
corona are not static, but display significant changes and variability even
in the case of the quiet solar atmosphere.
Several apparently different transient events take place in the outer
layers of the solar atmosphere (e.g., explosive events, blinkers, spicules,
bright points).
Overall mutual relations of plasma in ranges of chromospheric, transition region
and coronal temperatures should depend on presence and properties of these
transient events.
Especially solar network is of the particular interest as energy could
be channeled through the outer atmospheric layers in this target from
the photosphere to corona.
Moreover different global magnetic configuration (quiet sun, coronal hole)
can influence energy transport and dynamics of plasma in/above the solar
network as well.
Because of this we propose the simultaneous spectral line measurements with
the SOHO/CDS spectrometer in all layers of the outer solar atmosphere.
Our interest is focused on long time series of observations in the solar
network.
Results of our previous measurements (JOP 078, Gömöry et al., 2003, Hvar
Observatory Bulletin 27, 67-741) have shown that
effects of the transient events can be traced but
longer series of data than that one taken during the JOP 078 are
needed.
The main parameters used in this study (tested on the previous CDS data) will be
the intensities and the Doppler shifts of the selected spectral lines.
Autocorrelations and cross-correlations of these quantities allow us to
derive some information about energy transfer and mass motion in
solar outer atmosphere above/in the solar network
(Gömöry et al., 2003, contribution to the SOHO13
workshop2).

PARTICIPATING INSTRUMENTS:
The core of the program - the spectral measurements performed by
the SOHO/CDS spectrometer - have already been tested on July 23, 2003
as the VARDYN1-4 programs. The data have been inspected and it was clarified
that all 4 programs for the CDS spectrometers are prepared well providing
the data intended to be acquired. Extension of these tested programs to the
proposed operation of CDS is described below.
Additional observational data are proposed to be acquired simultaneously
with the proposed CDS spectral measurements, namely:
EIT patrol observations in all channels and measurements in 195 Åspectral
channel during the whole CDS run, MDI measurements of B, and
finally TRACE filtergrams in the selected bandpasses.
The TRACE observations are optional.

OPERATIONAL CONSIDERATIONS:
It is very important for our aim to run the main part of our CDS measurements
(VARDYN4) within the interval created by two successive EIT patrol
observations (FULL SUN 171/284/195/304), e.g., between 01:25-07.00 or within
other such intervals.
The total duration of the proposed observational run for CDS
is 8.3hours.
The run should be repeated in several days at different positions near the disk
center and in coronal hole. Direct selection of the target can
be performed several
hours or one day before the start of the particular run. No near real time
commanding of SOHO instruments and TRACE is required.
The program is intended to be performed within the MEDOC12 campaign
in the period November, 17-30, 2003.

DETAILED OBSERVING SEQUENCES - CDS:
All data are proposed to be obtained with the Normal Incidence Spectrometer
(NIS).
Various modes of CDS observations (1D position - full detector, 2D
raster - selected lines, 1D sequences - selected lines) are proposed
in a specific procedure. All modes (observing sequences) of CDS have already
been tested (July, 23, 2003).
The brightest CDS spectral lines were selected for our
aim with an attempt to cover wide range of temperatures
(10K-10K).
No rotation compensation is proposed for CDS so the slit should cover
several different structures during each run.
Alternation of the 4'' and 2'' slits are planned for the CDS sequence part 4.

CDS sequence part 5: 2D sequential raster near the disk center centred
at the position of the slit in the previous sequence part VARDYN4
(VARDYN3)

CDS sequence part 6: full detector (VARDYN2)

CDS sequence part 7: full detector (VARDYN1)

DETAILED OBSERVING SEQUENCES - EIT:
It is necessary for our aim to
obtain the patrol measurements of EIT (FULL SUN 171/284/195/304)
within the time interval in which the main part (CDS sequence parts 3-5)
of our CDS measurements will take place. The usual patrol measurements
taken at 01:00 UT, 07:00 UT, 13:00 UT and 19:00 UT are sufficient.
We need EIT observations in 195 Åspectral channel (usual CME watch)
during the whole CDS run.

DETAILED OBSERVING SEQUENCES - TRACE:
The TRACE part is scheduled as a repetition of image acquisition in
5 wavelengths in a cycle for a long time interval covering the SOHO/CDS
observing run. Pointing of TRACE should follow the CDS pointing.
Fine co-alignment of TRACE images with other (CDS, EIT) data will be
possible as the TRACE images should be taken in the same time as the
EIT patrol measurements and the CDS rasters.
Channels: Ly, UV continuum, CIV 1500Å, white light,
FeIX171Å
In case of some constraints of instrument the full set of images in all channels
can be taken only during the EIT patrol measurements and the CDS rasters
and a limited set of TRACE channels (Ly, UV continuum,
FeIX171Å) or just one channel (FeIX171Å)
can be defined for the main part of the CDS run (VARDYN4).
The TRACE observations with the partial requirements are not strictly
necessary for our aim, but they could help us significantly
to fulfil our scientific plans.